Pneumatic circuit design

TRAINING MANUAL ON PNEUMATICS PROJECT EXERCISES

Exercise 1 Direct control of Double Acting Cylinder Task: The piston of a double acting cylinder should advance on actuation of a push button

valve. After releasing the push button the cylinder retract back to its initial position automatically Condition: It is required that force should be exerted both during forward and return motion Suggestion for the positioning of equipment on the working plate

Table: List of Equipment

04

Double-acting Cylinder (Z1)

08

5/2 Way Directional Control Valve (Single Pivoted)

02

Distributor manifold ( 6 fold)

01

Air Service unit (Filter Regulator assembly)

1

TRAINING MANUAL ON PNEUMATICS Pneumatic circuit diagram

Fig. 01: Pneumatic Circuit diagram: Direct control of double acting cylinder

Selection: A Double acting cylinder has to be selected to meet the condition. A single piloted

valve can satisfy the task. Task

The piston rod of a double-working cylinder (Z1) should extend after actuating a button. After releasing the button (S1), the piston of the cylinder should retract automatically to its back position. Additions to the circuit diagram. All connections should be marked with the connection symbols according to ISO 5599 or RP 68 P. Pneumatic circuit diagram The cylinder is retracted in neutral position. The double-acting cylinder is directly controlled

by a manually operated 5/2 directional control valve (pos. 8). The spring cushioning mounted in the cylinder can be adjusted.

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TRAINING MANUAL ON PNEUMATICS

Exercise 2 Indirect control of Double Acting Cylinder Task: On actuation of a manual push button a Double acting cylinder with large volume has

to advance. After releasing the push button the cylinder should automatically return to home position Suggestion for the positioning of equipment on the working plate

Condition: It is required that force should be exerted only in during the forward motion Table: List of Equipment

04

Double-acting Cylinder (Z1)

10

5/2 Way Directional Control Valve (Single Piloted)

06

3/2 way Push button valve (NC)

02


01


3


Fig. 01: Pneumatic Circuit diagram: Indirect control of double acting cylinder

Selection: A Double acting cylinder has to be selected to meet the condition. A single piloted valve can satisfy the task. Aim

This exercise demonstrates the indirect control of a double-acting cylinder with a pneumatically operated 5/2 directional control valve. Task

The piston rod of a double-acting cylinder (drive element Z1), retracted in neutral position, should extend after actuating a button (controlling element S1). Control of the cylinder (Z1) should occur indirectly. After releasing the push-button (S1), the piston of the cylinder should retract automatically to its back position. Additions to the circuit plan. All connections should be marked with the connection symbols according to ISO 5599 or RP 68 P. Pneumatic circuit diagram

A pneumatically operated 5/2 directional control valve (actuator) is controlled with a manually operated 3/2 directional control valve (signaling element S1). The piston rod of the double-acting cylinder (actuating drive Z1) extends.

4


Exercise 2 Indirect control of Single Acting Cylinder Suggestion for the positioning of equipment on the working plate

03

Table: List of Equipment Single -acting Cylinder (Z1)

09

3/2 Way Directional Control Valve (Single Piloted) [Use 5/2 way Single piloted valve and block port B]

06


02


01


Aim

This exercises conveys know-how on the indirect control of cylinders, using a single-acting cylinder and a pneumatically operated 3/2 directional control valve as an example

5


Fig. 01: Pneumatic Circuit diagram: Indirect control of single acting cylinder

Task

The piston rod of a single-acting cylinder (Z1), retracted in neutral position, should advance after pushing an easily pressed button (S1). Note: for the control of a large volume cylinder (with a large piston diameter) an accordingly dimensioned directional control valve is necessary. The cylinder is mounted a slight distance from the button (S1). After releasing the manual pushbutton, the piston of the cylinder should retract automatically into its back position. Additions to the circuit diagram. All connections should be marked with the port symbols according to ISO 5599 or RP 68 P. Pneumatic circuit diagram

A manually operated 3/2 directional control valve in closed neutral position (start button S1) applies pressure to a pneumatically operated 3/2 directional control valve. A large volume single-acting cylinder is controlled via a pneumatically operated 3/2 directional control valve (pos. 9), the piston rod extends.

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Exercise 3 Speed Control of Single Acting Cylinder–Slow Speed Extension and Rapid Retraction Task: On actuation of a manual push button a Single acting cylinder should advance and

return to initial position after releasing the push button. The forward speed of the cylinder should be slow and controllable. The return speed should be faster than the nominal speed. Suggestion for the positioning of equipment on the working plate

Table: List of Equipment

03

Single acting Cylinder (Z1)

16

Quick Exhaust Valve

15

One way flow control valve

07


02


01


Aim

In addition to throttling the cylinder speed, this exercise shows how to achieve the highest possible speed when retracting the piston rod by using a quick-exhaust valve.

7


Pneumatic circuit diagram

Fig. 01: Pneumatic Circuit diagram: Speed Control of Single Acting Cylinder–Slow Speed Extension and Rapid Retraction

Task

The piston rod of a large volume, single-acting cylinder (Z1) is to extend with restricted, adjustable speed. The retraction of the piston rod should occur at the highest possible speed, also when the directional control valve (S1) is mounted a distance away from the cylinder. The cylinder is controlled by a manually operated button (S1). After releasing the button, the piston rod should retract automatically into its back position. Additions to the circuit diagram. All connections should be marked with the connection symbols according to ISO 5599 or RP 68 P. Pneumatic circuit diagram

Via the flow control valve with no return mounted in the working line the speed of the piston rod when extending can be infinitely restricted.

Through the quick-exhaust valve, also

mounted in the working line (as near to the cylinder port as possible), the cylinder piston retracts with the maximum possible speed.

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Exercise 4 Position Dependent Control of a Double Acting Cylinder with Mechanical Limit Switches Task: A Double acting cylinder is required to perform continuous reciprocating motions on

actuation of a detent manual push button. The piston should extend and retract over the complete stroke length as interrogated by mechanical limit switches. The speed of travel of the piston should be adjustable both during the forward and return motions Suggestion for the positioning of equipment on the working plate

04

01

Table: List of Equipment Double acting Cylinder (Z1)

11

01

Double Piloted 5/2 way Valve

15

02

One way flow control valves

06

01

3/2 way Push button valve (NC) with detent

13

02

3/2 way roller lever N.C. valve [Limit switches]

02

01


01

01


Aim

The displacement-dependent control of a double-acting cylinder by using l imit switches is demonstrated in this exercise

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Fig. 01: Pneumatic Circuit diagram: Position Dependent Control of a Double Acting Cylinder with Mechanical Limit Switches


If the start button (S0) is actuated and the feeler roll (S1) mounted in the ba ck end position of the cylinder (Z1) is also actuated, then the signal reaches port 14 of the impulse valve and switches it over, extending the piston rod. If limit switch S2 is contacted by the piston rod plunger, the signal arrives at port 12 of the impulse valve, the impulse valve switches back to the right switch position, the piston retracts. The limit switch S1 is actuated in the back end position of the piston; now the control is ready for a new start. The speed of both cylinder movements is infinitely adjusted with the flow control valves with non-return.

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Exercise 5 Logical Control with Shuttle and Twin-Pressure Valves Task: The Piston of double acting cylinder of a supply station supplies work pieces under the

following logical conditions: The start button (S0) or an auxiliary button (S1) is actuated and parts are available in the work piece magazine (B2) An optical display shows whether there are still enough parts available in the magazine. The cylinder should only retract into its back end position if it has actuation reached the front end position and an acknowledgement button (S4) is actuated. A 5/2 impulse valve is used as an actuator. Additionally: for scanning work pieces in the magazine (B2) it is not possible to use a mechanically operated signaler. The scanning should therefore occur in a non-contact manner through a reflex sensor. The working speed of the cylinder should be infinitely adjustable in both.

Example of application

Aim

This exercise uses a logical control to demonstrate the use of the logic basic functions OR (shuttle valve) or AND (two-pressure valve) in pneumatics. In this exercise, a proximity switching signaling element (reflex nozzle) i s also used. Pneumatic circuit diagram Signal pressure then reaches the control line 14 of the actuating drive (piston extends) if the

following conditions prove true: the button S0 OR the button S1 is actuated, AND the reflex nozzle B2 (amplifier pos. 26) has switched. Signal pressure then reaches the control line 12 (piston retracts) of the actuating drive if the limit switch S3 AND the button S4 are actuated. The reflex nozzle is supplied with low pressure of 0.4 bar via the pressure regulating valve with filter pos. 24. The pneumatic pressure display indicates whether the reflex nozzle or the amplifier is supplying a signal.

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Suggestion for the positioning of equipment on the working plate

Position Qty

Table: List of Equipment Description of component

04

01

Double acting Cylinder (Z1)

11

01

5/2 double Piloted Valve

13

02

3/2 way D.C. Valve (N.C.) Roller operated

18

01

Shuttle Valve, OR

19

02

Two Pressure Valves, AND

20

01

Pressure display,pneumatic,red,minimum pressure1.2bar

24

01

Pressure regulator with filter and regulator

25

01

Reflex Nozzle

26

01

Pneumatic Amplifier

15

02

One way flow control valves

07

01


02

01


01

01


12

TRAINING MANUAL ON PNEUMATICS Single and multiple OR or AND circuits with shuttle and twin pressure valve


Fig. 01: Pneumatic circuit diagram

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Exercise 6 Sequential Control of two double acting cylinders without overlapping signals Suggestion for the positioning of equipment on the working plate

Functional diagram

Functional diagram

Aim

This exercise helps to understand sequential controls and provides practical knowledge of setting up and commissioning a control system with two pneumatic drives. Practice in developing sequential diagram and pneumatic circuit diagram i s exercised.

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TRAINING MANUAL ON PNEUMATICS Example of application

Example of application

Task: Transport of Work pieces

Statement of the Application The Work pieces coming in on the right roller conveyor should be elevated and sent in a new direction. After actuating the start button, the piston of cylinder raises the work pieces to the height of the second roller conveyor with its elevating platform. Cylinder 1 remains in this position until cylinder 2 has pushed the work pieces from the elevating platform onto upper roller conveyor. When cylinder 2 has securely pushed all the work pieces onto the upper Roller conveyor, cylinder 1 moves down again only when cylinder has retracted into its lower end position does cylinder 2 also retract. Additionally a new start is only possible when cylinder is actually in its back end position. The working speed of both cylinders should be infinitely adjustable in both Directions the functional diagram is to be developed with actuator and drive element. Draw the circuit diagram with port symbols according to ISO 5599. Functional Diagram

The Status of the cylinder displacement and actuation of set and reset signals at the A double piloted directional control valve is shown in the Functional Diagram: Above In order to meet all the requirements a Pneumatic control circuit can be developed as shown below.

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TRAINING MANUAL ON PNEUMATICS Table: List of Equipment Description of components

Position

Qty.

04

02

Double-acting Cylinders (Z1 and Z2)

11

02

5/2 Way Directional Control Valves (Double piloted)

15

02

One way Flow control Valves (adjustable)

06

01

3/2 way Push button valve (NC)(S0)

13

04

3/2 way roller lever Limit switch (S1,S1,S3,S4)

02

01


01

01



Fig. 01: Pneumatic circuit diagram

16

TRAINING MANUAL ON PNEUMATICS Task "Transport of Workpiece"

The workpieces coming in on the right roller conveyor should be elevated and sent in a new direction. After actuating the start button (S0) the piston of cylinder 1 (Z1) raises the workpieces to the height of the second roller conveyor with its elevating platform. Cylinder 1 (Z1) remains in this position until cylinder 2 (Z2) has pushed the workpieces from the elevating platform onto the upper roller conveyor. When cylinder 2 (Z2) has securely pushed all the workpieces onto the upper roller conveyor, cylinder 1 (Z1) moves down again. Only when cylinder 1 (Z1) has retracted into its lower end position does cylinder 2 (Z2) also retract. Additionally: a new start is only possible when cylinder 2 (Z2) is actually in its back end position. The working speed of both cylinders should be infinitely adjustable in both directions. The functional diagram is to be developed wit h actuator and drive element. Drawing up the circ uit diagram with symbols and port symbols according to ISO 5599 or RP 68 P. Pneumatic circuit diagram

Two double-acting cylinders, retracted in neutral position, are displacement-dependently controlled by impulse valves. After actuating the start button S0, a control signal arrives at port 14 of the impulse valve for cylinder Z1 via the actuated limit switch S3. The piston rod of cylinder Z1 extends and in its front end position actuates the limit switch S2. The limit switch S2 sends a signal to the control port 14 of the impulse valve for cylinder 2. The piston rod of cylinder 2 extends into the front end position and actuates the limit switch S4. The limit switch S4 delivers the control signal to port 12 from the impulse valve for cylinder Z1. The piston of cylinder Z1 retracts and in its back end position actuates limit switch S1. The limit switch S1 delivers a signal to port 12 from the impulse valve for cylinder Z2, the piston retracts to the back end position. The system control is in its initial position.

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Pneumatic circuit design

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